TWI627619B - Touch panel driving apparatus - Google Patents

Abstract

The touch panel driving device generates a differential signal, and the differential signal corresponds to a detection result of the touch panel. The touch panel driving device includes a driving circuit, a first integration sampling circuit and a second integration sampling circuit. The first integration sampling circuit generates a first-end signal in the differential signal. The second integration sampling circuit generates a second-end signal in the differential signal. When the touch event does not occur, the level of the first-end signal and the level of the second-end signal fall within the common-mode signal range of the differential signal. When a touch event occurs, the first integration sampling circuit pulls up the level of the first-end signal beyond the range of the common mode signal, and the second integration sampling circuit pulls down the level of the second-end signal to the common mode signal Out of range.

Description

Touch panel driving device

The invention relates to a driving device for a touch panel.

The driving device of the touch panel is responsible for converting the charge change amount of the touch panel into an electrical signal. The touch panel driving device can amplify the sensing signal. The amplified sensing signal is beneficial to subsequent processing circuits for processing. Under the development trend of "thinning", touch panels are often integrated into display panels. The distance between the electrodes of the touch panel and the electrodes of the display panel is getting closer and closer, resulting in more and more serious interference effects caused by the display panel. Furthermore, the touch panel driving device amplifies the sensing signal, but the noise also increases with it.

Generally speaking, the larger the signal-to-noise ratio (SNR) of the signal output by the touch panel driving device, the better. The signal-to-noise ratio is ₁₀ log ₁₀ (S / N), where S represents a swing range of a signal. For example, the signal S may be a swing range of a signal output by a touch panel driving device when a touch event occurs on the touch panel, and N represents a swing range of noise. For example, the noise N may be a swing range of a signal output by the touch panel driving device when a touch event does not occur on the touch panel. When the signal-to-noise ratio of the signal output by the touch panel driving device is larger, the subsequent calculation circuit is easier to recognize the signal and noise. If the touch panel driving device can generate an output signal with a high swing and a high signal-to-noise ratio, subsequent calculation circuits can more easily and accurately process the sensing signal. How to realize a touch panel driving device with high swing and high signal-to-noise ratio is an important subject in the field of touch device technology.

The invention provides a touch panel driving device for generating a differential signal with a high amplitude and a high signal-to-noise ratio according to a detection result of the touch panel.

An embodiment of the present invention provides a touch panel driving device for driving a touch panel to generate a differential signal corresponding to a detection result of the touch panel. The touch panel driving device includes a driving circuit, a first integration sampling circuit and a second integration sampling circuit. During the first clock period, the driving circuit may provide a first driving signal to a driving line of the touch panel, and receive a sensing signal from a sensing line of the touch panel. During the second clock period, the driving circuit may provide a second driving signal to a driving line of the touch panel, and receive a sensing signal from a sensing line of the touch panel. The first integration sampling circuit is coupled to the driving circuit to receive the sensing signal during the first clock period. The first integration sampling circuit may generate a first-end signal in the differential signal. When the touch electrode of the sensing line does not detect a touch event, the level of the first end signal falls within the common mode signal range of the differential signal. When the touch electrode of the sensing line detects a touch event, the first integration sampling circuit pulls the level of the first end signal out of the common mode signal range according to the sensing signal. The second integration sampling circuit is coupled to the driving circuit to receive the sensing signal during the second clock period. The second integration sampling circuit may generate a second-end signal in the differential signal. When the touch electrode of the sensing line does not detect a touch event, the level of the second end signal falls within the range of the common mode signal. When the touch electrode of the sensing line detects a touch event, the second integration sampling circuit pulls the level of the second end signal out of the common mode signal range according to the sensing signal.

Based on the above, the touch panel driving device according to the embodiments of the present invention uses two integration sampling circuits to read the sensing signals of the touch panel, and then generates the first end signal and the second end signal in the differential signal, respectively. When the touch event does not occur, the level of the first-end signal and the second-end signal falls within the common-mode signal range of the differential signal. When a touch event occurs, the first integration sampling circuit can pull up the level of this first-end signal beyond the common-mode signal range, and the second integration sampling circuit can pull down the level of this second-end signal to a common Modal signal range. Therefore, the touch panel driving device according to the embodiments of the present invention can correspondingly generate a differential signal with a high swing and a high signal-to-noise ratio according to the detection result of the touch panel.

In order to make the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

The term "coupling (or connection)" used throughout the specification of this case (including the scope of patent application) can refer to any direct or indirect means of connection. For example, if the first device is described as being coupled (or connected) to a second device, it should be interpreted that the first device can be directly connected to the second device, or the first device can be connected through another device or some This connection means is indirectly connected to the second device. In addition, wherever possible, the same reference numbers are used in the drawings and embodiments to represent the same or similar parts. Elements / components / steps using the same reference numerals or using the same terms in different embodiments may refer to related descriptions.

FIG. 1 is a schematic diagram of a circuit block of a touch panel driving device 100 according to an embodiment of the present invention. The touch panel driving device 100 can drive the touch panel 10 and generate a differential signal Sdiff corresponding to a detection result of the touch panel 10. The touch panel driving device 100 includes a driving circuit 110, a first integration sampling circuit 120 and a second integration sampling circuit 130.

Referring to FIG. 1, the touch panel 10 is configured with one or more touch units (such as the touch unit 11), so as to detect whether a touch event occurs in the touch panel 10. Under different design requirements, the touch unit 11 has different layout structure designs. FIG. 1 illustrates an equivalent circuit of the touch unit 11. The touch unit 11 has a first electrode and a second electrode, wherein a mutual capacitor Cm is formed between the first electrode and the second electrode. In addition, the first electrode and the driving line have a parasitic capacitance Cs1, and the second electrode and the sensing line have a parasitic capacitance Cs2. The parasitic capacitance may also be referred to as a stray capacitor. According to different design requirements, the first electrode and the second electrode may be transparent electrodes, translucent electrodes, or opaque electrodes. For example, in this embodiment, indium tin oxide (ITO) may be used to implement the first electrode and the second electrode.

The touch panel 10 is configured with one or more driving lines. The driving circuit 110 may be coupled to the first electrode of the touch unit 11 through a driving line to provide a driving signal to the first electrode of the touch unit 11. The driving line has a parasitic impedance Rp1. The touch panel 120 is also configured with one or more sensing lines. The second electrode of the touch unit 11 is coupled to the sensing line. The sense line has a parasitic impedance Rp2. The sensing terminal of the driving circuit 110 is coupled to the sensing line of the touch panel 10 to read the touch information (sensing signal) of the touch unit 11 in the touch panel 10. According to different design requirements, the driving line and the sensing line may be transparent wires, translucent wires or opaque wires. For example, in this embodiment, the driving line and the sensing line may be implemented by using ITO wires.

In the sensing operation of the touch unit 11, the driving circuit 110 provides a driving signal to the first electrode of the touch unit 11 through a driving line, and the driving circuit 110 synchronously receives the sensing signal of the touch unit 11 through the sensing line. . The first integration sampling circuit 120 is coupled to the driving circuit 110 to receive a sensing signal. The second integration sampling circuit 130 is coupled to the driving circuit 110 to receive a sensing signal. For example, during the first clock period, the driving circuit 110 may provide a first driving signal to a driving line of the touch panel 10, receive a sensing signal from a sensing line of the touch panel 10, and transmit the sensing signal to First integration sampling circuit 120. During the second clock period, the driving circuit 110 may provide a second driving signal to a driving line of the touch panel 10, and receive a sensing signal from a sensing line of the touch panel 10, and transmit the sensing signal to a second integral sampling. Circuit 130. For the operation of the driving circuit 110 during the third clock period, refer to the related description of the first clock period. For the operation of the driving circuit 110 during the fourth clock period, refer to the related description of the second clock period. The operation during the rest of the clock can be deduced by analogy.

The first integration sampling circuit 120 may generate a first end signal Sd1 in the differential signal Sdiff. The second integration sampling circuit 130 may generate a second terminal signal Sd2 in the differential signal Sdiff. When the touch electrode of the sensing line (for example, the electrode of the touch unit 11) does not detect a touch event, the level of the first end signal Sd1 and the level of the second end signal Sd2 fall within the range of the differential signal Sdiff. Common-mode signal range. For example, assuming that there is no fluctuation amount of environmental interference, when no touch event occurs, the first integration sampling circuit 120 and the second integration sampling circuit 130 may respectively separate the level of the first-end signal Sd1 from the second level The level of the end signal Sd2 is maintained near the common voltage Vref. The level of the common voltage Vref can be determined according to design requirements. For example, the level of the common voltage Vref may be 1.65V or other voltage levels. In some embodiments, the common voltage Vref may be an electrode signal of the touch panel 10 or a common reference voltage of the electrodes of the touch panel 10.

When the sensing event of the sensing line (such as the electrode of the touch unit 11) detects a touch event, the first integration sampling circuit 120 pulls up the level of the first end signal Sd1 according to the sensing signal of the sensing line. Outside the common-mode signal range, and the second integration sampling circuit 130 pulls down the level of the second-end signal Sd2 beyond the common-mode signal range according to the sensing signal of the sensing line. For example, when a touch event occurs, the first integration sampling circuit 120 performs a forward integration (upward integration) operation on the sensing signal of the sensing line. Therefore, during the integration process, the level of the first end signal Sd1 will be From the common voltage Vref is gradually pulled up. Similarly, when a touch event occurs, the second integration sampling circuit 130 performs an inverse integration (downward integration) operation on the sensing signal of the sensing line, so the level of the second end signal Sd2 during the integration operation Will be gradually pulled down from the common voltage Vref.

The reset period of the integration operation of the first integration sampling circuit 120 and the second integration sampling circuit 130 may be dynamically adjusted according to design requirements (or application requirements). In some embodiments, if certain design requirements (or application requirements) require high-speed operation, the reset period of the integration operation can be dynamically reduced (reset earlier). In other embodiments, when the reset period of the integration operation is increased (reset is performed later), the pressure difference between the first-end signal Sd1 and the second-end signal Sd2 will be increased in order to meet Design requirements (or application requirements) for high swing and high signal-to-noise ratio (SNR). Therefore, the touch panel driving device 100 according to this embodiment can correspondingly generate a differential signal Sdiff with a high swing and a high signal-to-noise ratio according to the detection result of the touch panel 10.

FIG. 2 is a schematic circuit block diagram illustrating the touch panel driving device 100 shown in FIG. 1 according to an embodiment of the present invention. In the embodiment shown in FIG. 2, the driving circuit 110 includes a first switch SW11, a second switch SW12, a third switch SW13, and a fourth switch SW14. A first terminal of the first switch SW11 is coupled to the first driving signal Vin. A second terminal of the first switch SW11 is coupled to a driving line of the touch panel 10. The control terminal of the first switch SW11 is controlled by the clock signal clk1. Based on the control of the clock signal clk1, the first switch SW11 can transmit the first driving signal Vin to the driving line of the touch panel during the first clock period, and not transmit the first driving signal Vin during the second clock period. The first terminal of the second switch SW12 is coupled to the second driving signal. In the embodiment shown in FIG. 2, the common voltage Vref of the touch panel 10 is used as the second driving signal. A second terminal of the second switch SW12 is coupled to a driving line of the touch panel 10. The control terminal of the second switch SW12 is controlled by the clock signal clk2. Based on the control of the clock signal clk2, the second switch SW12 can transmit the second driving signal (common voltage Vref) to the driving line of the touch panel 10 during the second clock period and not transmit during the first clock period. The second driving signal (common voltage Vref). The levels of the first driving signal Vin and the second driving signal (common voltage Vref) may be determined according to design requirements. For example, the first driving signal Vin may be a fixed voltage, and the level of the first driving signal Vin may be greater than the level of the second driving signal (common voltage Vref).

A first terminal of the third switch SW13 is coupled to the first integration sampling circuit 120. The second terminal of the third switch SW13 is coupled to the sensing line of the touch panel 10. The control terminal of the third switch SW13 is controlled by the clock signal clk1. Based on the control of the clock signal clk1, the third switch SW13 can transmit the sensing signal of the sensing line of the touch panel 10 to the first integration sampling circuit 120 during the first clock period, and not transmit the touch signal during the second clock period. A sensing signal of a sensing line of the control panel 10. A first terminal of the fourth switch SW14 is coupled to the second integration sampling circuit 130. The second terminal of the fourth switch SW14 is coupled to the sensing line of the touch panel 10. The control terminal of the fourth switch SW14 is controlled by the clock signal clk2. Based on the control of the clock signal clk2, the fourth switch SW14 can transmit the sensing signal of the sensing line of the touch panel 10 to the second integration sampling circuit 130 during the second clock period, and not transmit the touch signal during the first clock period. A sensing signal of a sensing line of the control panel 10.

FIG. 3 is a schematic diagram illustrating a signal timing of the circuit shown in FIG. 2 when a touch event does not occur on the touch panel 10 according to an embodiment of the present invention. FIG. 4 is a schematic diagram illustrating signal timing of the circuit shown in FIG. 2 when a touch event occurs on the touch panel 10 according to an embodiment of the present invention. In FIGS. 3 and 4, the horizontal axis represents time, and the vertical axis represents voltage. Please refer to FIG. 2, FIG. 3 and FIG. 4. The pulses of the clock signal clk1 and the pulses of the clock signal clk2 do not overlap each other. Therefore, during the first clock period, the first switch SW11 and the third switch SW13 are turned on, and the second switch SW12 and the fourth switch SW14 are turned off. During the second clock period, the first switch SW11 and the third switch SW13 are turned off, and the second switch SW12 and the fourth switch SW14 are turned on.

The first integration sampling circuit 120 includes a reverse integration circuit 121, a delta-adding correlated double sampling (DCDS) circuit 122, and a forward integration circuit 123. The inverse integration circuit 121 is coupled to the third switch SW13. When the third switch SW13 is turned on, the inverse integration circuit 121 may receive a sensing signal of a sensing line of the touch panel 10. The inverse integration circuit 121 may perform an inverse integration operation on the sensing signals of the sensing lines of the touch panel 10 to output the integration result Vca1 to the incremental correlation double sampling circuit 122. That is, based on the sensing signal, the level of the integration result Vca1 will be gradually lowered during the inverse integration operation until the integration result Vca1 is reset (as shown in FIGS. 3 and 4). As shown). Because of the touch event, the decrease in the integration result Vca1 (the integrated voltage level) shown in FIG. 4 is different from the decrease in the integration result Vca1 shown in FIG. 3.

The incremental correlation double sampling circuit 122 is coupled to the output terminal of the inverse integration circuit 121 to receive the integration result Vca1. The incremental correlation double sampling circuit 122 is controlled by a first control signal ϕ1 and a second control signal ϕ2. Timing examples of the first control signal ϕ1 and the second control signal ϕ2 are shown in FIGS. 3 and 4. The pulse width of the first control signal ϕ1 defines the “sampling period” of the incremental correlation double sampling circuit 122, and the pulse width of the second control signal ϕ2 defines the “output period” of the incremental correlation double sampling circuit 122. Based on the control of the first control signal ϕ1, the incremental correlation double sampling circuit 122 may sample the integration result Vca1 during the sampling period to obtain the sampling result. Based on the control of the second control signal ϕ2, the incremental correlation double sampling circuit 122 can use the reference voltage VL to pump this sampling result during the output period to obtain a pumping result. After the output period ends, the inverse integration circuit 121 is reset. That is, after the pulse of the second control signal ϕ2 ends, a pulse appears in the reset signal Reset_CA to reset the inverse integration circuit 121 (as shown in FIGS. 3 and 4). The level of the reference voltage VL can be determined according to design requirements. For example, assuming that when the touch electrode of the sensing line of the touch panel 10 does not detect a touch event, the level of the sampling result of the delta-correlation double sampling circuit 122 is a certain “untouched level”, then The level of the reference voltage VL may be set as the "non-touch level". The level of the reference voltage VL may be lower than the level of the common voltage Vref. When no touch event occurs (as shown in FIG. 3), because the level of the sampling result of the incremental correlation double sampling circuit 122 is the same as the level of the reference voltage VL, the incremental correlation double sampling circuit 122 has no extra charge transfer. Give the forward integration circuit 123. When a touch event occurs (as shown in FIG. 4), because the level of the sampling result of the incremental correlation double sampling circuit 122 is different from the level of the reference voltage VL, the incremental correlation double sampling circuit 122 will remove the excess charge Transfer to the forward integration circuit 123.

The forward integration circuit 123 is coupled to the output of the incrementally correlated double sampling circuit 122 to receive the pumping result. The forward integration circuit 123 may perform a forward integration operation on the pumping result to output the integration result as the first end signal Sd1. When a touch event occurs, because the pumping result of the incrementally correlated double sampling circuit 122 includes a charge, the level of the first-end signal Sd1 will be gradually pulled up during the forward integration operation. Until the first-end signal Sd1 is reset. The pulse of the reset signal Reset_Int resets the forward integration circuit 123, thereby resetting the first-end signal Sd1 (as shown in FIG. 4). When no touch event occurs, the incremental correlation double sampling circuit 122 has no excess charge transferred to the forward integration circuit 123, so the forward integration circuit 123 can maintain the level of the first-end signal Sd1 to the common level of the differential signal Sdiff. Mode signal range. For example, the forward integration circuit 123 may maintain the level of the first-end signal Sd1 at a common voltage Vref (as shown in FIG. 3).

Similar to the first integration sampling circuit 120, the second integration sampling circuit 130 includes a forward integration circuit 131, an incremental correlation double sampling circuit 132, and a reverse integration circuit 133. The forward integration circuit 131 is coupled to the fourth switch SW14. When the fourth switch SW14 is turned on, the forward integration circuit 131 may receive a sensing signal of a sensing line of the touch panel 10. The forward integration circuit 131 may perform a forward integration operation on the sensing signal to output the integration result Vca2 to the incremental correlation double sampling circuit 122. That is, based on the sensing signal, the level of the integration result Vca2 will be gradually raised during the forward integration operation until the integration result Vca2 is reset (as shown in FIGS. 3 and 4). As shown). Because of the touch event, the rising range (integrated voltage level) of the integration result Vca2 shown in FIG. 4 is different from the rising range of the integration result Vca2 shown in FIG. 3.

The incremental correlation double sampling circuit 132 is coupled to the output terminal of the forward integration circuit 131 to receive the integration result Vca2. The incremental correlation double sampling circuit 132 is controlled by a first control signal ϕ1 and a second control signal ϕ2. Based on the control of the first control signal ϕ1, the incremental correlation double sampling circuit 132 may sample the integration result Vca2 during the sampling period to obtain the sampling result. Based on the control of the second control signal ϕ2, the incremental correlation double sampling circuit 132 may use the reference voltage VH to pump this sampling result during the output period to obtain a pumping result. After the output period ends, the forward integration circuit 131 is reset (as shown in FIGS. 3 and 4). The level of the reference voltage VH can be determined according to design requirements. For example, assuming that when the touch electrode of the sensing line of the touch panel 10 does not detect a touch event, the level of the sampling result of the incremental correlation double sampling circuit 132 is a certain “untouched level”, then The level of the reference voltage VH may be set as the "non-touch level". The level of the reference voltage VH may be higher than the level of the common voltage Vref. When the touch event does not occur, because the level of the integration result Vca2 is the same as the level of the reference voltage VH, the incremental correlation double sampling circuit 132 has no extra charge transferred to the inverse integration circuit 133. When a touch event occurs, because the level of the sampling result of the delta-correlation double sampling circuit 132 is different from the level of the reference voltage VH, the delta-correlation double sampling circuit 132 transfers the excess charge to the inverse integration circuit 133 .

The inverse integration circuit 133 is coupled to the output of the delta-correlation double sampling circuit 132 to receive the pumping result. The reverse integration circuit 133 may perform a reverse integration operation on the pumping result to output the integration result as the second end signal Sd2. When a touch event occurs, because the pumping result of the incremental correlation double sampling circuit 132 includes a charge, the level of the second-end signal Sd2 will be gradually lowered during the inverse integration operation. Until the second-end signal Sd2 is reset. The pulse of the reset signal Reset_Int resets the inverse integration circuit 133, thereby resetting the second-end signal Sd2 (as shown in FIG. 4). When no touch event occurs, the incremental correlation double sampling circuit 132 has no excess charge transferred to the inverse integration circuit 133, so the inverse integration circuit 133 can maintain the level of the second-end signal Sd2 to the common level of the differential signal Sdiff. Mode signal range. For example, the inverse integration circuit 133 may maintain the level of the second-end signal Sd2 at a common voltage Vref (as shown in FIG. 3).

In the embodiment shown in FIG. 2, the inverse integration circuit 121 includes an operational amplifier 121 a, a feedback capacitor 121 b, and a reset switch 121 c. The inverting input terminal of the operational amplifier 121 a is coupled to the third switch SW13 to receive a sensing signal from a sensing line of the touch panel 10. The non-inverting input terminal of the operational amplifier 121a is coupled to a common voltage Vref. The output terminal of the operational amplifier 121a is coupled to the incremental correlation double sampling circuit 122 to provide the integration result Vca1. A first terminal and a second terminal of the feedback capacitor 121b are respectively coupled to an inverting input terminal of the operational amplifier 121a and an output terminal of the operational amplifier 121a. The first terminal and the second terminal of the reset switch 121c are respectively coupled to an inverting input terminal of the operational amplifier 121a and an output terminal of the operational amplifier 121a. The control terminal of the reset switch 121c is controlled by a reset signal Reset_CA. Based on the control of the reset signal Reset_CA, the reset switch 121c can reset the charge of the feedback capacitor 121b, that is, reset the integration result Vca1, as shown in FIGS. 3 and 4.

In the embodiment shown in FIG. 2, the incremental correlation double sampling circuit 122 includes a switch 122 a, a switch 122 b, a switch 122 c, a switch 122 d, and a sampling capacitor 122 e. The first terminal of the switch 122a is coupled to the output terminal of the inverse integration circuit 121 to receive the integration result Vca1. The control terminal of the switch 122a is controlled by the first control signal ϕ1. The first terminal of the switch 122b is coupled to the reference voltage VL. The control terminal of the switch 122b is controlled by the second control signal ϕ2. A first terminal of the sampling capacitor 122e is coupled to a second terminal of the switch 122a and a second terminal of the switch 122b. A first terminal of the switch 122c is coupled to a second terminal of the sampling capacitor 122e. The second terminal of the switch 122c is coupled to the common voltage Vref. The control terminal of the switch 122c is controlled by the first control signal ϕ1. A first terminal of the switch 122d is coupled to the second terminal of the sampling capacitor 122e, and a second terminal of the switch 122d is coupled to the forward integration circuit 123 to provide a pumping result. The control terminal of the switch 122d is controlled by the second control signal ϕ2.

Based on the control of the first control signal ϕ1, when the switches 122a and 122c are turned on and the switches 122b and 122d are turned off (sampling period), the sampling capacitor 122e can sample (store) the integration result Vca1 to obtain the sampling result. Based on the control of the second control signal ϕ2, when the switches 122b and 122d are turned on and the switches 122a and 122c are turned off (during the output period), the incremental correlation double sampling circuit 122 can use the reference voltage VL to pump this sampling result and Get pumping results. When no touch event occurs (as shown in Figure 3), because the level of the first terminal of the sampling capacitor 122e is the same as the level of the reference voltage VL, the first terminal of the sampling capacitor 122e is switched to the reference voltage. After VL, no excess charge is transferred from the sampling capacitor 122e to the forward integration circuit 123. When a touch event occurs (as shown in FIG. 4), because the level of the first terminal of the sampling capacitor 122e is greater than the level of the reference voltage VL, the first terminal of the sampling capacitor 122e is switched to the reference voltage VL After that, the sampling capacitor 122e transfers the excess charge to the forward integration circuit 123.

In the embodiment shown in FIG. 2, the forward integration circuit 123 includes an operational amplifier 123 a, a feedback capacitor 123 b, and a reset switch 123 c. The inverting input terminal of the operational amplifier 123a is coupled to the incremental correlation double sampling circuit 122 to receive the pumping result. The non-inverting input terminal of the operational amplifier 123a is coupled to a common voltage Vref. The output terminal of the operational amplifier 123a outputs an integration result as the first terminal signal Sd1. A first terminal and a second terminal of the feedback capacitor 123b are respectively coupled to an inverting input terminal of the operational amplifier 123a and an output terminal of the operational amplifier 123a. A first terminal and a second terminal of the reset switch 123c are respectively coupled to an inverting input terminal of the operational amplifier 123a and an output terminal of the operational amplifier 123a. When no touch event occurs (as shown in FIG. 3), the incremental correlation double sampling circuit 122 has no extra charge transferred to the feedback capacitor 123b, so the forward integration circuit 123 can maintain the level of the first-end signal Sd1 at The common-mode signal range of the differential signal Sdiff. For example, the forward integration circuit 123 may maintain the level of the first-end signal Sd1 at the common voltage Vref. When a touch event occurs (as shown in FIG. 4), because the pumping result of the incrementally correlated double sampling circuit 122 includes a charge, the level of the first-end signal Sd1 will gradually be pulled up until the The first-end signal Sd1 is reset.

In the embodiment shown in FIG. 2, the forward integration circuit 131 includes an operational amplifier 131 a, a feedback capacitor 131 b, and a reset switch 131 c. The inverting input terminal of the operational amplifier 131 a is coupled to the fourth switch SW14 to receive a sensing signal from a sensing line of the touch panel 10. The non-inverting input terminal of the operational amplifier 131a is coupled to a common voltage Vref. An output terminal of the operational amplifier 131a is coupled to the incremental correlation double sampling circuit 132 to provide an integration result Vca2. A first terminal and a second terminal of the feedback capacitor 131b are respectively coupled to an inverting input terminal of the operational amplifier 131a and an output terminal of the operational amplifier 131a. A first terminal and a second terminal of the reset switch 131c are respectively coupled to an inverting input terminal of the operational amplifier 131a and an output terminal of the operational amplifier 131a. The control terminal of the reset switch 131c is controlled by a reset signal Reset_CA. Based on the control of the reset signal Reset_CA, the reset switch 131c can reset the charge of the feedback capacitor 131b, that is, reset the integration result Vca2.

In the embodiment shown in FIG. 2, the incremental correlation double sampling circuit 132 includes a switch 132a, a switch 132b, a switch 132c, a switch 132d, and a sampling capacitor 132e. The first terminal of the switch 132a is coupled to the output terminal of the forward integration circuit 131 to receive the integration result Vca2. The control terminal of the switch 132a is controlled by the first control signal ϕ1. The first terminal of the switch 132b is coupled to the reference voltage VH. The control terminal of the switch 132b is controlled by the second control signal ϕ2. A first terminal of the sampling capacitor 132e is coupled to a second terminal of the switch 132a and a second terminal of the switch 132b. A first terminal of the switch 132c is coupled to a second terminal of the sampling capacitor 132e. The second terminal of the switch 132c is coupled to the common voltage Vref. The control terminal of the switch 132c is controlled by the first control signal ϕ1. A first terminal of the switch 132d is coupled to a second terminal of the sampling capacitor 132e. The second terminal of the switch 132d is coupled to the inverse integration circuit 133 to provide a pumping result. The control terminal of the switch 132d is controlled by the second control signal ϕ2.

Based on the control of the first control signal ϕ1, when the switches 132a and 132c are turned on and the switches 132b and 132d are turned off (during the sampling period), the sampling capacitor 132e can sample (store) the integration result Vca2 to obtain the sampling result. Based on the control of the second control signal ϕ2, when the switches 132b and 132d are turned on and the switches 132a and 132c are turned off (during the output period), the incremental correlation double sampling circuit 132 can use the reference voltage VH to pump this sampling result and Get pumping results. When no touch event occurs (as shown in Figure 3), because the level of the first end of the sampling capacitor 132e is the same as the level of the reference voltage VH, the first end of the sampling capacitor 132e is switched to the reference voltage. After VH, no excess charge is transferred from the sampling capacitor 132e to the inverse integration circuit 133. When a touch event occurs (as shown in FIG. 4), because the level of the first end of the sampling capacitor 132e is smaller than the level of the reference voltage VH, the first end of the sampling capacitor 132e is switched to the reference voltage VH After that, the sampling capacitor 132e transfers the excess charge to the inverse integration circuit 133.

In the embodiment shown in FIG. 2, the inverse integration circuit 133 includes an operational amplifier 133a, a feedback capacitor 133b, and a reset switch 133c. The inverting input terminal of the operational amplifier 133a is coupled to the incremental correlation double sampling circuit 132 to receive the pumping result. The non-inverting input terminal of the operational amplifier 133a is coupled to a common voltage Vref. The output terminal of the operational amplifier 133a outputs an integration result as a second terminal signal Sd2. A first terminal and a second terminal of the feedback capacitor 133b are respectively coupled to an inverting input terminal of the operational amplifier 133a and an output terminal of the operational amplifier 133a. A first terminal and a second terminal of the reset switch 133c are respectively coupled to an inverting input terminal of the operational amplifier 133a and an output terminal of the operational amplifier 133a. When no touch event occurs (as shown in FIG. 3), the incremental correlation double sampling circuit 132 has no excess charge transferred to the feedback capacitor 133b, so the inverse integration circuit 133 can maintain the level of the second-end signal Sd2 at The common-mode signal range of the differential signal Sdiff. For example, the inverse integration circuit 133 may maintain the level of the second-end signal Sd2 at the common voltage Vref. When a touch event occurs (as shown in FIG. 4), because the pumping result of the incremental correlation double sampling circuit 132 includes a charge, the level of the second-end signal Sd2 will be gradually lowered until the The second-end signal Sd2 is reset.

The control terminal of the reset switch 123c and the control terminal of the reset switch 133c are both controlled by the reset signal Reset_Int. Based on the control of the reset signal Reset_Int, the reset switch 123c can reset the charge of the feedback capacitor 123b, that is, reset the first-end signal Sd1. Based on the control of the reset signal Reset_Int, the reset switch 133c can reset the charge of the feedback capacitor 133b, that is, reset the second-end signal Sd2. The reset period of the reset signal Reset_Int can be dynamically adjusted according to design requirements (or application requirements). In some embodiments, if certain design requirements (or application requirements) require high-speed operation, the reset period of the reset signal Reset_Int can be dynamically reduced (reset earlier). In other embodiments, when the reset period of the reset signal Reset_Int is increased (reset is performed later), the pressure difference between the first-end signal Sd1 and the second-end signal Sd2 becomes larger, so as to meet Design requirements (or application requirements) for high swing and high signal-to-noise ratio. Therefore, the touch panel driving device 100 according to this embodiment can correspondingly generate a differential signal Sdiff with a high swing and a high signal-to-noise ratio according to the detection result of the touch panel 10.

FIG. 5 is a schematic circuit block diagram of a touch panel driving device 500 according to another embodiment of the present invention. The touch panel driving device 500 can drive the touch panel 10 and generate a differential signal Sdiff corresponding to a detection result of the touch panel 10. The touch panel driving device 500 includes a driving circuit 110, a first integration sampling circuit 120, a second integration sampling circuit 130, and a voltage supply circuit 540. The touch panel 10, the touch panel driving device 500, the driving circuit 110, the first integration sampling circuit 120, and the second integration sampling circuit 130 shown in FIG. 5 can be referred to the touch panel 10 and the touch panel shown in FIGS. 1 to 4. Relevant descriptions of the driving device 100, the driving circuit 110, the first integration sampling circuit 120, and the second integration sampling circuit 130 are deduced by analogy, so they are not described again.

In the embodiment shown in FIG. 5, the voltage providing circuit 540 is coupled to the first integration sampling circuit 120 to receive the first representative voltage. The voltage supply circuit 540 is coupled to the second integration sampling circuit 130 to receive a second representative voltage. According to the first representative voltage and the second representative voltage, the voltage providing circuit 540 may generate a reference voltage VL and a reference voltage VH correspondingly. The reference voltage VL is supplied to an incrementally correlated double sampling circuit in the first integration sampling circuit 120. The reference voltage VH is supplied to an incrementally correlated double sampling circuit in the second integration sampling circuit 130.

FIG. 6 is a schematic circuit block diagram illustrating the touch panel driving device 500 shown in FIG. 5 according to an embodiment of the present invention. In the embodiment shown in FIG. 6, the first integration sampling circuit 120 includes an inverse integration circuit 121, an incremental correlation double sampling circuit 122, and a forward integration circuit 123. The second integration sampling circuit 130 includes a forward integration circuit 131, an incremental correlation double sampling circuit 132, and a reverse integration circuit 133. The reverse integration circuit 121, the incremental correlation double sampling circuit 122, the forward integration circuit 123, the forward integration circuit 131, the incremental correlation double sampling circuit 132, and the reverse integration circuit 133 shown in FIG. 6 can be referred to FIGS. 1 to 4 The relevant descriptions are analogized, so they will not be repeated. In the embodiment shown in FIG. 6, the first terminal signal Sd1 as shown in FIG. 2 is used as the first representative voltage, and the second terminal signal Sd2 as shown in FIG. 2 is used as the second representative. Voltage.

In the embodiment shown in FIG. 6, the voltage supply circuit 540 includes a first comparator 541, a second comparator 542, an operation circuit 543, a first digital analog converter (DAC) 544, and a second digital analog converter.器 545. A first input terminal of the first comparator 541 is coupled to the first integration sampling circuit 120 to receive a first representative voltage (a first terminal signal Sd1). The second input terminal of the first comparator 541 is coupled to the common voltage Vref. The first comparator 541 may compare the first terminal signal Sd1 and the common voltage Vref to obtain a first comparison result. An output of the first comparator 541 outputs a first comparison result. A first input terminal of the second comparator 542 is coupled to the second integration sampling circuit 130 to receive a second representative voltage (a second terminal signal Sd2). The second input terminal of the second comparator 542 is coupled to the common voltage Vref. The second comparator 542 may compare the second terminal signal Sd2 and the common voltage Vref to obtain a second comparison result. An output of the second comparator 542 outputs a second comparison result.

The operation circuit 543 is coupled to the first comparator 541 to receive the first comparison result. The operation circuit 543 is coupled to the second comparator 542 to receive the second comparison result. In some embodiments, the arithmetic circuit 543 may perform an algorithm according to the first comparison result and the second comparison result to calculate a first voltage value and a second voltage value. In other embodiments, the arithmetic circuit 543 may find the first voltage value and the second voltage value from a look-up table according to the first comparison result and the second comparison result. The algorithm or the lookup table can be set according to design requirements.

The first digital-to-analog converter 544 is coupled to the operation circuit 543 to receive the first voltage value. The first digital-to-analog converter 544 may convert the first voltage value into a reference voltage VL, and output the reference voltage VL to the incremental correlation double sampling circuit 122 in the first integration sampling circuit 120. The arithmetic circuit 543 may set the reference voltage VL to a certain “first non-touch level”, so that when the touch event does not occur on the touch panel 10 (as shown in FIG. 3), the incremental correlation double sampling circuit 122 does not. The excess charge is transferred to the forward integration circuit 123, so that the level of the first-end signal Sd1 output by the forward integration circuit 123 is maintained within the common mode signal range of the differential signal Sdiff (for example, maintained at the common voltage Vref). The first comparator 541 can maintain the stability of the reference voltage VL.

The second digital-to-analog converter 545 is coupled to the operation circuit 543 to receive the second voltage value. The second digital analog converter 545 may convert the second voltage value into a reference voltage VH, and output the reference voltage VH to the incremental correlation double sampling circuit 132 in the second integration sampling circuit 130. The arithmetic circuit 543 can set the reference voltage VH to a certain “second untouched level”, so that when the touch panel 10 does not touch the event (as shown in FIG. 3), the incremental correlation double sampling circuit 132 is not redundant. The charge is transferred to the inverse integration circuit 133, so that the level of the first-end signal Sd1 output by the inverse integration circuit 133 is maintained in the common mode signal range of the differential signal Sdiff (for example, the common voltage Vref). The second comparator 542 can maintain the stability of the reference voltage VH.

FIG. 7 is a schematic circuit block diagram illustrating the touch panel driving device 500 shown in FIG. 5 according to another embodiment of the present invention. In the embodiment shown in FIG. 7, the first integration sampling circuit 120 includes a reverse integration circuit 121, an incremental correlation double sampling circuit 122, and a forward integration circuit 123. The second integration sampling circuit 130 includes a forward integration circuit 131, an incremental correlation double sampling circuit 132, and a reverse integration circuit 133. The reverse integration circuit 121, the delta correlation double sampling circuit 122, the forward integration circuit 123, the forward integration circuit 131, the delta correlation double sampling circuit 132, and the reverse integration circuit 133 shown in FIG. 7 can be referred to FIGS. 1 to 4 The relevant descriptions are analogized, so they will not be repeated. In the embodiment shown in FIG. 7, the integration result Vca1 output by the inverse integration circuit 121 in the first integration sampling circuit 120 is used as the first representative voltage of the first integration sampling circuit 120, and in the first The integration result Vca2 output by the forward integration circuit 131 in the two integration sampling circuit 130 is used as the second representative voltage of the second integration sampling circuit 130.

In the embodiment shown in FIG. 7, the voltage providing circuit 540 includes a first analog digital converter (ADC) 546, a second analog digital converter 547, an operation circuit 543, a first digital analog converter 544, and a first Two-digit analog converter 545. An input terminal of the first analog-to-digital converter 546 is coupled to an output terminal of the inverse integration circuit 121 in the first integration sampling circuit 120 to receive a first representative voltage (integration result Vca1). An output terminal of the first analog-to-digital converter 546 outputs a first voltage value. An input terminal of the second analog-to-digital converter 547 is coupled to an output terminal of the forward integration circuit 131 in the second integration sampling circuit 130 to receive a second representative voltage (integration result Vca2). An output terminal of the second analog-to-digital converter 547 outputs a second voltage value.

The operation circuit 543 is coupled to the first analog-to-digital converter 546 to receive the first voltage value. The operation circuit 543 is coupled to the second analog-to-digital converter 547 to receive the second voltage value. In some embodiments, the arithmetic circuit 543 may perform an algorithm according to the first voltage value and the second voltage value to calculate a third voltage value and a fourth voltage value. In other embodiments, the arithmetic circuit 543 may find the third voltage value and the fourth voltage value from a look-up table according to the first voltage value and the second voltage value. The algorithm or the lookup table can be set according to design requirements.

The first digital-to-analog converter 544 is coupled to the operation circuit 543 to receive the third voltage value. The first digital analog converter 544 may convert the third voltage value into a reference voltage VL, and output the reference voltage VL to the incremental correlation double sampling circuit 122 in the first integration sampling circuit 120. The arithmetic circuit 543 may set the reference voltage VL to a certain “first non-touch level”, so that when the touch event does not occur on the touch panel 10 (as shown in FIG. 3), the incremental correlation double sampling circuit 122 does not. The excess charge is transferred to the forward integration circuit 123, so that the level of the first-end signal Sd1 output by the forward integration circuit 123 is maintained within the common mode signal range of the differential signal Sdiff (for example, maintained at the common voltage Vref). The voltage supply circuit 540 can maintain the stability of the reference voltage VL in a feedback manner.

The second digital-to-analog converter 545 is coupled to the operation circuit 543 to receive the fourth voltage value. The second digital analog converter 545 may convert the fourth voltage value into a reference voltage VH, and output the reference voltage VH to the incremental correlation double sampling circuit 132 in the second integration sampling circuit 130. The arithmetic circuit 543 can set the reference voltage VH to a certain “second untouched level”, so that when the touch panel 10 does not touch the event (as shown in FIG. 3), the incremental correlation double sampling circuit 132 is not redundant. The charge is transferred to the inverse integration circuit 133, so that the level of the first-end signal Sd1 output by the inverse integration circuit 133 is maintained in the common mode signal range of the differential signal Sdiff (for example, the common voltage Vref). The voltage supply circuit 540 can maintain the stability of the reference voltage VH in a feedback manner.

FIG. 8 is a schematic circuit block diagram illustrating the touch panel driving device 500 shown in FIG. 5 according to another embodiment of the present invention. In the embodiment shown in FIG. 8, the first integration sampling circuit 120 includes a reverse integration circuit 121, an incremental correlation double sampling circuit 122, and a forward integration circuit 123. The second integration sampling circuit 130 includes a forward integration circuit 131, an incremental correlation double sampling circuit 132, and a reverse integration circuit 133. The reverse integration circuit 121, the incremental correlation double sampling circuit 122, the forward integration circuit 123, the forward integration circuit 131, the incremental correlation double sampling circuit 132, and the reverse integration circuit 133 shown in FIG. 8 can be referred to FIGS. 1 to 4 The relevant descriptions are analogized, so they will not be repeated. In the embodiment shown in FIG. 8, the first terminal signal Sd1 as shown in FIG. 2 is used as the first representative voltage, and the second terminal signal Sd2 as shown in FIG. 2 is used as the second representative. Voltage.

In the embodiment shown in FIG. 8, the voltage supply circuit 540 includes an analog-to-digital converter 841, an operation circuit 842, and a digital-to-analog converter 843. The analog-to-digital converter 841 is coupled to the first integration sampling circuit 120 to receive a first representative voltage (a first-end signal Sd1). The analog-to-digital converter 841 is coupled to the second integration sampling circuit 130 to receive a second representative voltage (second end signal Sd2). The analog-to-digital converter 841 can convert the first representative voltage (the first terminal signal Sd1) into a first voltage value, and convert the second representative voltage (the second terminal signal Sd2) into a second voltage value.

The operation circuit 842 is coupled to the analog-to-digital converter 841 to receive the first voltage value and the second voltage value. In some embodiments, the arithmetic circuit 842 may perform an algorithm according to the first voltage value and the second voltage value to calculate a third voltage value and a fourth voltage value. In other embodiments, the arithmetic circuit 842 may find the third voltage value and the fourth voltage value from a lookup table according to the first comparison result and the second comparison result. The algorithm or the lookup table can be set according to design requirements.

The digital-to-analog converter 843 is coupled to the operation circuit 842 to receive the third voltage value and the fourth voltage value. The digital analog converter 843 may convert the third voltage value into a reference voltage VL, and output the reference voltage VL to the incremental correlation double sampling circuit 122 in the first integration sampling circuit 120. The arithmetic circuit 842 may set the reference voltage VL to a certain "first non-touch level", so that when the touch event does not occur on the touch panel 10 (as shown in FIG. 3), the incremental correlation double sampling circuit 122 does not. The excess charge is transferred to the forward integration circuit 123, so that the level of the first-end signal Sd1 output by the forward integration circuit 123 is maintained within the common-mode signal range of the differential signal Sdiff (for example, maintained at the common voltage Vref). The voltage supply circuit 540 can maintain the stability of the reference voltage VL in a feedback manner.

The digital analog converter 843 may further convert the fourth voltage value into a reference voltage VH, and output the reference voltage VH to the incremental correlation double sampling circuit 132 in the second integration sampling circuit 130. The arithmetic circuit 842 may set the reference voltage VH to a certain “second untouched level”, so that when the touch panel 10 does not touch the event (as shown in FIG. 3), the incremental correlation double sampling circuit 132 is not redundant. The charge is transferred to the inverse integration circuit 133, so that the level of the first-end signal Sd1 output by the inverse integration circuit 133 is maintained in the common mode signal range of the differential signal Sdiff (for example, the common voltage Vref). The voltage supply circuit 540 can maintain the stability of the reference voltage VH in a feedback manner.

FIG. 9 is a schematic circuit block diagram of a touch panel driving device 900 according to another embodiment of the present invention. The touch panel driving device 900 can drive the touch panel 10 and generate a differential signal Sdiff corresponding to a detection result of the touch panel 10. The touch panel driving device 900 includes a driving circuit 110, a first integration sampling circuit 120, a second integration sampling circuit 130, a baseline compensator circuit 950, and an analog-to-digital converter 960. The touch panel 10, the touch panel driving device 900, the driving circuit 110, the first integration sampling circuit 120, and the second integration sampling circuit 130 shown in FIG. 9 can refer to the touch panel 10 and the touch panel shown in FIGS. 1 to 4. Relevant descriptions of the driving device 100, the driving circuit 110, the first integration sampling circuit 120, and the second integration sampling circuit 130 are deduced by analogy, so they are not described again.

In the embodiment shown in FIG. 9, the baseline compensation circuit 950 has a pair of differential input terminals and a pair of differential output terminals. The differential input terminal pair of the baseline compensation circuit 950 is coupled to the first integration sampling circuit 120 and the second integration sampling circuit 130 to receive the differential signal Sdiff. The analog-to-digital converter 960 has a differential input terminal pair. The differential input terminal pair of the analog-to-digital converter 960 is coupled to the differential output terminal pair of the baseline compensation circuit 950.

In the embodiment shown in FIG. 9, the baseline compensation circuit 950 includes a differential amplifier Adiff, a first switch SW51, a second switch SW52, a third switch SW53, a fourth switch SW54, a fifth switch SW55, a sixth switch SW56, and a third switch. Seven switch SW57, eighth switch SW58, ninth switch SW59, tenth switch SW510, eleventh switch SW511, twelfth switch SW512, first capacitor C51, second capacitor C52, third capacitor C53, fourth capacitor C54 A fifth capacitor C55 and a sixth capacitor C56. The inverting output terminal and the non-inverting output terminal of the differential amplifier Adiff serve as a differential output terminal pair of the baseline compensation circuit 950.

The first terminal of the first switch SW51 is coupled to the first integration sampling circuit 120 to receive the first terminal signal Sd1 in the differential signal Sdiff. A first terminal of the seventh switch SW57 is coupled to the second integration sampling circuit 130 to receive a second terminal signal Sd2 in the differential signal Sdiff. The control terminal of the first switch SW51 and the control terminal of the seventh switch SW57 are both controlled by the clock signal clk2. The control terminal of the second switch SW52 is controlled by the clock signal clk1. A first terminal of the first capacitor C51 is coupled to a second terminal of the first switch SW51. The second terminal of the first capacitor C51 is coupled to the inverting input terminal of the differential amplifier Adiff. A first terminal of the fourth capacitor C54 is coupled to a second terminal of the seventh switch SW57. The second terminal of the fourth capacitor C54 is coupled to the non-inverting input terminal of the differential amplifier Adiff.

A first terminal of the second switch SW52 is coupled to a second terminal of the first switch SW51. The second terminal of the second switch SW52 is coupled to a reference voltage (such as a ground voltage). The first terminal of the third switch SW53 is coupled to the inverting input terminal of the differential amplifier Adiff. The control terminal of the third switch is controlled by the clock signal clk2. A first terminal of the fourth switch SW54 is coupled to a second terminal of the third switch SW53. The second terminal of the fourth switch SW54 is coupled to a reference voltage (such as a ground voltage). The control terminal of the fourth switch SW54 is controlled by the clock signal clk1. A first terminal of the second capacitor C52 is coupled to a second terminal of the third switch SW53. The second terminal of the second capacitor C52 is coupled to the non-inverting output terminal of the differential amplifier Adiff. The first terminal of the third capacitor C53 is coupled to the inverting input terminal of the differential amplifier Adiff. A first terminal of the fifth switch SW55 is coupled to a second terminal of the third capacitor C53. The second terminal of the fifth switch SW55 is coupled to a reference voltage (such as a ground voltage). The control terminal of the fifth switch SW55 is controlled by the clock signal clk2. A first terminal of the sixth switch SW56 is coupled to a second terminal of the third capacitor C53. The second terminal of the sixth switch SW56 is coupled to the non-inverting output terminal of the differential amplifier Adiff. The control terminal of the sixth switch SW56 is controlled by the clock signal clk1.

A first terminal of the eighth switch SW58 is coupled to a second terminal of the seventh switch SW57. The second terminal of the eighth switch SW58 is coupled to a reference voltage (such as a ground voltage). The control terminal of the eighth switch SW58 is controlled by the clock signal clk1. The first terminal of the ninth switch SW59 is coupled to the non-inverting input terminal of the differential amplifier Adiff. The control terminal of the ninth switch SW59 is controlled by the clock signal clk2. A first terminal of the tenth switch SW510 is coupled to a second terminal of the ninth switch SW59. The second terminal of the tenth switch SW510 is coupled to a reference voltage (such as a ground voltage). The control terminal of the tenth switch SW510 is controlled by the clock signal clk1. The first terminal of the fifth capacitor C55 is coupled to the second terminal of the ninth switch. The second terminal of the fifth capacitor C55 is coupled to a reference voltage (such as a ground voltage). The first terminal of the sixth capacitor C56 is coupled to the non-inverting input terminal of the differential amplifier Adiff. The first terminal of the eleventh switch SW511 is coupled to the second terminal of the sixth capacitor C56. The second terminal of the eleventh switch SW511 is coupled to a reference voltage (such as a ground voltage). The control end of the eleventh switch SW511 is controlled by the clock signal clk2. The first terminal of the twelfth switch SW512 is coupled to the second terminal of the sixth capacitor C56. The second terminal of the twelfth switch SW512 is coupled to a reference voltage (such as a ground voltage). The control terminal of the twelfth switch SW512 is controlled by the clock signal clk1.

In summary, the touch panel driving device 100, 500 or 900 according to the embodiments of the present invention uses two integration sampling circuits 120 and 130 to read the sensing signals of the touch panel 10. The integration sampling circuits 120 and 130 generate a first-end signal Sd1 and a second-end signal Sd2 in the differential signal Sdiff, respectively. When no touch event occurs on the touch panel 10, the level of the first-end signal Sd1 and the second-end signal Sd2 falls within the common-mode signal range of the differential signal Sdiff. For example, the levels of the first-end signal Sd1 and the second-end signal Sd2 may be maintained at a common voltage Vref. When a touch event occurs on the touch panel 10, the first integration sampling circuit 120 may pull up the level of the first-end signal Sd1 beyond the common-mode signal range, and the second integration sampling circuit 130 may connect the second end The level of the signal Sd2 is pulled out of the common-mode signal range. Therefore, the touch panel driving apparatus 100, 500, or 900 according to the embodiments of the present invention can correspondingly generate a differential signal Sdiff with a high swing and a high signal-to-noise ratio according to the detection result of the touch panel 10. Based on the signal characteristics of high swing and high signal-to-noise ratio, the touch panel driving device according to the embodiments of the present invention can solve the interference problem caused by the too close distance between the touch panel 10 and the lower panel (such as the display panel).

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

10‧‧‧Touch Panel
11‧‧‧Touch Unit
100‧‧‧touch panel driving device
110‧‧‧Drive circuit
120‧‧‧The first integration sampling circuit
121‧‧‧ Inverse Integrating Circuit
121a‧‧‧ Operational Amplifier
121b‧‧‧Feedback capacitor
121c‧‧‧Reset switch
122‧‧‧ Incremental Correlation Double Sampling Circuit
122a, 122b, 122c, 122d‧‧‧ Switches
122e‧‧‧sampling capacitor
123‧‧‧forward integration circuit
123a‧‧‧ Operational Amplifier
123b‧‧‧Feedback capacitor
123c‧‧‧Reset switch
130‧‧‧Second integration sampling circuit
131‧‧‧ Forward Integrating Circuit
131a‧‧‧ Operational Amplifier
131b‧‧‧Feedback capacitor
131c‧‧‧Reset switch
132‧‧‧ Incremental Correlation Double Sampling Circuit
132a, 132b, 132c, 132d‧‧‧ Switches
132e‧‧‧sampling capacitor
133‧‧‧ Inverse integration circuit
133a‧‧‧ Operational Amplifier
133b‧‧‧Feedback capacitor
133c‧‧‧Reset switch
500‧‧‧touch panel driving device
540‧‧‧voltage supply circuit
541‧‧‧first comparator
542‧‧‧Second Comparator
543‧‧‧ Operation Circuit
544‧‧‧The first digital analog converter
545‧‧‧ Second Digital Analog Converter
546‧‧‧The first analog digital converter
547‧‧‧Second Analog Digital Converter
841‧‧‧ Analog Digital Converter
842‧‧‧ Operation Circuit
843‧‧‧Digital Analog Converter
900‧‧‧ touch panel driving device
950‧‧‧baseline compensation circuit
960‧‧‧Analog digital converterϕ1‧‧‧First control signal
Adiff‧‧‧ Differential Amplifier
C51‧‧‧First capacitor
C52‧‧‧Second capacitor
C53‧‧‧Third capacitor
C54‧‧‧Fourth capacitor
C55‧‧‧Fifth capacitor
C56‧‧‧sixth capacitor
clk1, clk2‧‧‧ clock signal
Cm‧‧‧ Mutual capacitance
Cs1, Cs2‧‧‧parasitic capacitance
Reset_CA‧‧‧ reset signal
Reset_Int‧‧‧ reset signal
Rp1, Rp2‧‧‧parasitic impedance
Sd1‧‧‧First-end signal
Sd2‧‧‧ second-end signal
Sdiff‧‧‧ Differential Signal
SW11‧‧‧The first switch
SW12‧‧‧Second switch
SW13‧‧‧Third switch
SW14‧‧‧Fourth switch
SW51‧‧‧The first switch
SW52‧‧‧Second switch
SW53‧‧‧Third switch
SW54‧‧‧Fourth switch
SW55‧‧‧Fifth switch
SW56‧‧‧Sixth switch
SW57‧‧‧Seventh switch
SW58‧‧‧eighth switch
SW59‧‧‧Ninth Switch
SW510‧‧‧Tenth switch
SW511‧‧‧Eleventh Switch
SW512‧‧‧The twelfth switch
Vca1, Vca2‧‧‧point result
VH‧‧‧Reference voltage
Vin‧‧‧first drive signal
VL‧‧‧Reference voltage
Vref‧‧‧ common voltage

FIG. 1 is a schematic diagram of a circuit block of a touch panel driving device according to an embodiment of the present invention. FIG. 2 is a schematic circuit block diagram illustrating the touch panel driving device shown in FIG. 1 according to an embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a signal timing of the circuit shown in FIG. 2 when no touch event occurs on the touch panel according to an embodiment of the present invention. FIG. 4 is a schematic diagram illustrating signal timing of the circuit shown in FIG. 2 when a touch event occurs on the touch panel according to an embodiment of the present invention. FIG. 5 is a schematic circuit block diagram of a touch panel driving device according to another embodiment of the present invention. FIG. 6 is a schematic circuit block diagram illustrating the touch panel driving device shown in FIG. 5 according to an embodiment of the present invention. FIG. 7 is a schematic circuit block diagram illustrating the touch panel driving device shown in FIG. 5 according to another embodiment of the present invention. FIG. 8 is a schematic circuit block diagram illustrating the touch panel driving device shown in FIG. 5 according to another embodiment of the present invention. FIG. 9 is a schematic circuit block diagram of a touch panel driving device according to another embodiment of the present invention.

Claims (20)

A touch panel driving device is used to drive a touch panel to generate a differential signal corresponding to the detection result of the touch panel. The touch panel driving device includes: a driving circuit for a first A first driving signal is provided to a driving line of the touch panel during a clock period, a sensing signal is received from a sensing line of the touch panel, and a second driving signal is provided to a second clock period. The driving line and the sensing signal are received from the sensing line; a first integration sampling circuit is coupled to the driving circuit to receive the sensing signal during the first clock period to generate the differential signal; A first-end signal, wherein when a touch event is not detected by a sensing electrode of the sensing line, the level of the first-end signal falls within a common-mode signal range of the differential signal, and when the sensing When the sensing electrode of the measuring line detects the touch event, the first integration sampling circuit pulls the level of the first end signal out of the common mode signal range according to the sensing signal; and a second Integral sampling circuit, coupled to The driving circuit is configured to receive the sensing signal during the second clock period to generate a second-end signal in the differential signal, wherein when the touch electrode of the sensing line does not detect the touch event The level of the second-end signal falls within the common-mode signal range, and when the touch event is detected by the sensing electrode of the sensing line, the second integration sampling circuit changes the signal according to the sensing signal. The level of the second-end signal is pulled out of the common-mode signal range. The touch panel driving device according to item 1 of the patent application scope, wherein the driving circuit includes: a first switch for transmitting the first driving signal to the touch panel during the first clock period; A driving line, and the first driving signal is not transmitted during the second clock period; a second switch for transmitting the second driving signal to the driving line of the touch panel during the second clock period, And the second driving signal is not transmitted during the first clock period; a third switch is coupled to the first integration sampling circuit, and is used for the sensing line of the touch panel during the first clock period The sensing signal is transmitted to the first integration sampling circuit, and the sensing signal is not transmitted during the second clock period; and a fourth switch is coupled to the second integration sampling circuit for the second integration sampling circuit. The sensing signal of the sensing line of the touch panel is transmitted to the second integration sampling circuit during a clock period, and the sensing signal is not transmitted during the first clock period. The touch panel driving device according to item 2 of the scope of patent application, wherein the first integration sampling circuit includes: an inverse integration circuit coupled to the third switch to receive the sensing signal for detecting the sensing signal. An inverse integration operation is performed on the measured signal to output a first integration result. An incremental correlation double sampling circuit is coupled to an output terminal of the inverse integration circuit to receive the first integration result for a sampling period. Sampling the first integration result to obtain a sampling result, and performing a pumping process on the sampling result using a reference voltage during an output period to obtain a pumping result; and a forward integration circuit coupled to the increment An output terminal of the correlated double sampling circuit receives the pumping result, and performs a forward integration operation on the pumping result to output a second integration result as the first terminal signal. The touch panel driving device according to item 3 of the scope of patent application, wherein when the sensing electrode of the sensing line does not detect the touch event, the level of the sampling result is an untouched level, and The level of the reference voltage is set to the untouched level. The touch panel driving device according to item 3 of the scope of patent application, wherein the inverse integration circuit includes: an operational amplifier having an inverting input terminal, a non-inverting input terminal and an output terminal, wherein the inverting circuit An input terminal is coupled to the third switch to receive the sensing signal, the non-inverting input terminal is coupled to a common voltage, and the output terminal of the operational amplifier is coupled to the incremental correlation double sampling circuit to provide the first An integration result; a feedback capacitor, a first terminal and a second terminal of which are respectively coupled to the inverting input terminal and the output terminal of the operational amplifier; and a reset switch, which has a first terminal and a The second terminal is respectively coupled to the inverting input terminal and the output terminal of the operational amplifier. The touch panel driving device according to item 3 of the scope of patent application, wherein the incremental correlation double sampling circuit includes: a fifth switch having a first terminal, a second terminal, and a control terminal, wherein the fifth The first terminal of the switch is coupled to the output terminal of the inverse integration circuit to receive the first integration result, and the control terminal of the fifth switch is controlled by a first control signal; a sixth switch having A first terminal, a second terminal, and a control terminal, wherein the first terminal of the sixth switch is coupled to the reference voltage, and the control terminal of the sixth switch is controlled by a second control signal; A first terminal of the sampling capacitor is coupled to the second terminal of the fifth switch and the second terminal of the sixth switch; a seventh switch has a first terminal, a second terminal, and a control terminal Wherein the first terminal of the seventh switch is coupled to a second terminal of the sampling capacitor, the second terminal of the seventh switch is coupled to a common voltage, and the control terminal of the seventh switch is controlled To the first control signal; and an eighth switch having a first terminal, a second terminal and A control terminal, wherein the first terminal of the eighth switch is coupled to the second terminal of the sampling capacitor, the second terminal of the eighth switch is coupled to the forward integration circuit to provide the pumping result, and The control terminal of the eighth switch is controlled by the second control signal. The touch panel driving device according to item 3 of the scope of patent application, wherein the forward integration circuit includes: an operational amplifier having an inverting input terminal, a non-inverting input terminal and an output terminal, wherein the inverting An input terminal is coupled to the incremental correlation double sampling circuit to receive the pumping result, the non-inverting input terminal is coupled to a common voltage, and the output terminal of the operational amplifier outputs the second integration result as the first terminal A signal; a feedback capacitor, a first terminal and a second terminal of which are respectively coupled to the inverting input terminal and the output terminal of the operational amplifier; and a reset switch, which has a first terminal and a second terminal The terminals are respectively coupled to the inverting input terminal and the output terminal of the operational amplifier. The touch panel driving device according to item 2 of the scope of patent application, wherein the second integration sampling circuit comprises: a forward integration circuit coupled to the fourth switch to receive the sensing signal for detecting the sensing signal; The measured signal performs a forward integration operation to output a first integration result. An incremental correlation double sampling circuit is coupled to an output of the forward integration circuit to receive the first integration result for a sampling period. Sampling the first integration result to obtain a sampling result, and performing a pumping process on the sampling result using a reference voltage during an output period to obtain a pumping result; and a reverse integration circuit coupled to the increment An output terminal of the correlated double sampling circuit receives the pumping result, and performs an inverse integration operation on the pumping result to output a second integration result as the second terminal signal. The touch panel driving device according to item 8 of the scope of patent application, wherein the level of the sampling result is an untouched level when the sensing electrode of the sensing line does not detect the touch event, and The level of the reference voltage is set to the untouched level. The touch panel driving device according to item 8 of the scope of patent application, wherein the forward integration circuit includes: an operational amplifier having an inverting input terminal, a non-inverting input terminal and an output terminal, wherein the inverting An input terminal is coupled to the fourth switch to receive the sensing signal, the non-inverting input terminal is coupled to a common voltage, and the output terminal of the operational amplifier is coupled to the incremental correlation double sampling circuit to provide the first An integration result; a feedback capacitor, a first terminal and a second terminal of which are respectively coupled to the inverting input terminal and the output terminal of the operational amplifier; and a reset switch, which has a first terminal and a The second terminal is respectively coupled to the inverting input terminal and the output terminal of the operational amplifier. The touch panel driving device according to item 8 of the scope of patent application, wherein the incrementally correlated double sampling circuit includes: a fifth switch having a first terminal, a second terminal, and a control terminal, wherein the fifth The first terminal of the switch is coupled to the output terminal of the forward integration circuit to receive the first integration result, and the control terminal of the fifth switch is controlled by a first control signal; a sixth switch having A first terminal, a second terminal, and a control terminal, wherein the first terminal of the sixth switch is coupled to the reference voltage, and the control terminal of the sixth switch is controlled by a second control signal; A first terminal of the sampling capacitor is coupled to the second terminal of the fifth switch and the second terminal of the sixth switch; a seventh switch has a first terminal, a second terminal, and a control terminal Wherein the first terminal of the seventh switch is coupled to a second terminal of the sampling capacitor, the second terminal of the seventh switch is coupled to a common voltage, and the control terminal of the seventh switch is controlled To the first control signal; and an eighth switch having a first terminal, a second terminal and A control terminal, wherein the first terminal of the eighth switch is coupled to the second terminal of the sampling capacitor, the second terminal of the eighth switch is coupled to the inverse integration circuit to provide the pumping result, and The control terminal of the eighth switch is controlled by the second control signal. The touch panel driving device according to item 8 of the scope of patent application, wherein the inverse integration circuit includes: an operational amplifier having an inverting input terminal, a non-inverting input terminal and an output terminal, wherein the inverting circuit An input terminal is coupled to the incremental correlation double sampling circuit to receive the pumping result, the non-inverting input terminal is coupled to a common voltage, and the output terminal of the operational amplifier outputs the second integration result as the second terminal A signal; a feedback capacitor, a first terminal and a second terminal of which are respectively coupled to the inverting input terminal and the output terminal of the operational amplifier; and a reset switch, which has a first terminal and a second terminal The terminals are respectively coupled to the inverting input terminal and the output terminal of the operational amplifier. The touch panel driving device according to item 1 of the scope of patent application, further comprising: a voltage supply circuit coupled to the first integration sampling circuit to receive a first representative voltage and coupled to the second integration sampling circuit Receiving a second representative voltage for generating a first reference voltage and a second reference voltage corresponding to the first representative voltage and the second representative voltage, wherein the first reference voltage is provided to the first integral; A first incremental correlation double sampling circuit in the sampling circuit, and the second reference voltage is provided to a second incremental correlation double sampling circuit in the second integration sampling circuit. The touch panel driving device according to item 13 of the application, wherein the first representative voltage is the first terminal signal and the second representative voltage is the second terminal signal. The touch panel driving device according to item 14 of the patent application scope, wherein the voltage supply circuit includes: a first comparator having a first input terminal, a second input terminal and an output terminal, wherein the first The first input terminal of the comparator is coupled to the first integration sampling circuit to receive the first representative voltage, the second input terminal of the first comparator is coupled to a common voltage, and the first comparator The output terminal outputs a first comparison result. A second comparator has a first input terminal, a second input terminal, and an output terminal. The first input terminal of the second comparator is coupled to the first comparator. Two integration sampling circuits to receive the second representative voltage, the second input terminal of the second comparator is coupled to the common voltage, and the output terminal of the second comparator outputs a second comparison result; an operation circuit , Coupled to the first comparator to receive the first comparison result, coupled to the second comparator to receive the second comparison result, and used to calculate according to the first comparison result and the second comparison result -A first voltage value and A second voltage value; a first digital analog converter coupled to the arithmetic circuit to receive the first voltage value for converting the first voltage value into the first reference voltage and the first reference voltage Output to the first incremental correlation double sampling circuit in the first integration sampling circuit; and a second digital analog converter coupled to the operation circuit to receive the second voltage value for the second voltage The value is converted into the second reference voltage, and the second reference voltage is output to the second incremental correlation double sampling circuit in the second integration sampling circuit. The touch panel driving device according to item 14 of the scope of patent application, wherein the voltage supply circuit includes: an analog-to-digital converter coupled to the first integration sampling circuit to receive the first representative voltage and coupled to the The second integration sampling circuit receives the second representative voltage, wherein the analog-to-digital converter converts the first representative voltage to a first voltage value, and the analog-to-digital converter converts the second representative voltage to a second voltage. A voltage value; an arithmetic circuit coupled to the analog-to-digital converter to receive the first voltage value and the second voltage value for calculating a third voltage according to the first voltage value and the second voltage value Value and a fourth voltage value; and a digital analog converter coupled to the arithmetic circuit to receive the third voltage value and the fourth voltage value for converting the third voltage value to the first reference voltage , Outputting the first reference voltage to the first incremental correlation double sampling circuit in the first integration sampling circuit, converting the fourth voltage value to the second reference voltage, and the second reference voltage Output to the second sampling increment of the second integrator circuit correlated double sampling circuit. The touch panel driving device according to item 13 of the scope of patent application, wherein the first representative voltage is a first integration result output by an inverse integration circuit in the first integration sampling circuit, and the second representative The voltage is a second integration result output by a forward integration circuit in the second integration sampling circuit. The touch panel driving device according to item 17 of the patent application scope, wherein the voltage supply circuit includes: a first analog digital converter having an input terminal and an output terminal, wherein the first analog digital converter An input terminal is coupled to an output terminal of the inverse integration circuit in the first integration sampling circuit to receive the first representative voltage, and the output terminal of the first analog-to-digital converter outputs a first voltage value; The second analog-to-digital converter has an input terminal and an output terminal, wherein the input terminal of the second analog-to-digital converter is coupled to an output terminal of the forward integration circuit in the second integration sampling circuit for receiving. The second representative voltage, and the output terminal of the second analog digital converter outputs a second voltage value; an arithmetic circuit coupled to the first analog digital converter to receive the first voltage value, coupled to The second analog-to-digital converter receives the second voltage value to calculate a third voltage value and a fourth voltage value according to the first voltage value and the second voltage value; a first digital The ratio converter is coupled to the operation circuit to receive the third voltage value, to convert the third voltage value to the first reference voltage, and output the first reference voltage to the first integration sampling circuit. The first incremental correlation double sampling circuit; and a second digital analog converter coupled to the arithmetic circuit to receive the fourth voltage value for converting the fourth voltage value to the second reference voltage, And outputting the second reference voltage to the second incremental correlation double sampling circuit in the second integration sampling circuit. The touch panel driving device according to item 1 of the scope of patent application, further comprising: a baseline compensation circuit having a differential input terminal pair and a differential output terminal pair, wherein the differential input terminal of the baseline compensation circuit A pair coupled to the first integration sampling circuit and the second integration sampling circuit to receive the differential signal; and an analog-to-digital converter having a differential input terminal pair, wherein the differential input of the analog-to-digital converter An end pair is coupled to the differential output end pair of the baseline compensation circuit. The touch panel driving device according to item 19 of the scope of patent application, wherein the baseline compensation circuit includes: a first switch having a first terminal, a second terminal, and a control terminal, wherein the first switch The first terminal is coupled to the first integration sampling circuit to receive the first terminal signal in the differential signal, and the control terminal of the first switch is controlled by a first clock signal; a second switch, There is a first terminal, a second terminal, and a control terminal, wherein the first terminal of the second switch is coupled to the second terminal of the first switch, and the second terminal of the second switch is coupled to A reference voltage, and the control terminal of the second switch is controlled by a second clock signal; a first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is coupled Connected to the second terminal of the first switch; a differential amplifier having an inverting input terminal, a non-inverting input terminal, an inverting output terminal and a non-inverting output terminal, wherein The inverting input terminal is coupled to the second terminal of the first capacitor, and the inverting terminal of the differential amplifier is The output terminal and the non-inverting output terminal are used as the differential output terminal pair of the baseline compensation circuit; a third switch having a first terminal, a second terminal and a control terminal, wherein the first of the third switch Terminal is coupled to the inverting input terminal of the differential amplifier, and the control terminal of the third switch is controlled by the first clock signal; a fourth switch has a first terminal, a second terminal and A control terminal, wherein the first terminal of the fourth switch is coupled to the second terminal of the third switch, the second terminal of the fourth switch is coupled to the reference voltage, and the The control terminal is controlled by the second clock signal; a second capacitor having a first terminal and a second terminal, wherein the first terminal of the second capacitor is coupled to the second terminal of the third switch And the second terminal of the second capacitor is coupled to the non-inverting output terminal of the differential amplifier; a third capacitor has a first terminal and a second terminal, wherein the first capacitor of the third capacitor A terminal is coupled to the inverting input terminal of the differential amplifier; a fifth switch having a first terminal, a second terminal and A control terminal, wherein the first terminal of the fifth switch is coupled to the second terminal of the third capacitor, the second terminal of the fifth switch is coupled to the reference voltage, and the fifth terminal of the fifth switch The control terminal is controlled by the first clock signal; a sixth switch having a first terminal, a second terminal, and a control terminal, wherein the first terminal of the sixth switch is coupled to the third capacitor; The second terminal, the second terminal of the sixth switch is coupled to the non-inverting output terminal of the differential amplifier, and the control terminal of the sixth switch is controlled by the second clock signal; a seventh The switch has a first terminal, a second terminal, and a control terminal, wherein the first terminal of the seventh switch is coupled to the second integration sampling circuit to receive the second terminal signal in the differential signal, The control terminal of the seventh switch is controlled by the first clock signal; an eighth switch has a first terminal, a second terminal, and a control terminal, wherein the first terminal of the eighth switch is coupled Connected to the second terminal of the seventh switch, the second terminal of the eighth switch is coupled to the reference voltage, and the The control terminal is controlled by the second clock signal. A fourth capacitor has a first terminal and a second terminal, wherein the first terminal of the fourth capacitor is coupled to the second terminal of the seventh switch. The second terminal of the fourth capacitor is coupled to the non-inverting input terminal of the differential amplifier; a ninth switch having a first terminal, a second terminal and a control terminal, wherein the ninth switch The first terminal is coupled to the non-inverting input terminal of the differential amplifier, and the control terminal of the ninth switch is controlled by the first clock signal; a tenth switch having a first terminal and a first terminal; Two terminals and a control terminal, wherein the first terminal of the tenth switch is coupled to the second terminal of the ninth switch, the second terminal of the tenth switch is coupled to the reference voltage, and the tenth The control terminal of the switch is controlled by the second clock signal; a fifth capacitor having a first terminal and a second terminal, wherein the first terminal of the fifth capacitor is coupled to the second switch of the ninth switch; A second terminal, and the second terminal of the fifth capacitor is coupled to the reference voltage; a sixth capacitor having a first terminal and a second terminal Terminal, wherein the first terminal of the sixth capacitor is coupled to the non-inverting input terminal of the differential amplifier; an eleventh switch having a first terminal, a second terminal, and a control terminal, wherein the first terminal The first terminal of the eleventh switch is coupled to the second terminal of the sixth capacitor, the second terminal of the eleventh switch is coupled to the reference voltage, and the control terminal of the eleventh switch is controlled At the first clock signal; and a twelfth switch having a first terminal, a second terminal, and a control terminal, wherein the first terminal of the twelfth switch is coupled to the sixth capacitor The second terminal, the second terminal of the twelfth switch is coupled to the reference voltage, and the control terminal of the twelfth switch is controlled by the second clock signal.